Archives par mot-clé : Tress

better to know...?, climate-debate

More trees do not always create a cooler planet, Clark University geographer finds

by Clark University, Feb 14, 203221 in WUWT

WORCESTER, Mass. — New research by Christopher A. Williams, an environmental scientist and professor in Clark University‘s Graduate School of Geography, reveals that deforestation in the U.S. does not always cause planetary warming, as is commonly assumed; instead, in some places, it actually cools the planet. A peer-reviewed study by Williams and his team, “Climate Impacts of U.S. Forest Loss Span Net Warming to Net Cooling,” published today (Feb. 12) in Science Advances. The team’s discovery has important implications for policy and management efforts that are turning to forests to mitigate climate change.

It is well established that forests soak up carbon dioxide from the air and store it in wood and soils, slowing the accumulation of greenhouse gases in the atmosphere; however, that is not their only effect on climate. Forests also tend to be darker than other surfaces, said Professor Williams, causing them to absorb more sunlight and retain heat, a process known as “the albedo effect.”

“We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both carbon and albedo effects,” said Professor Williams. It is important to consider the albedo effect of forests alongside their well-known carbon storage when aiming to cool the planet, he adds.

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climate-debate

Listen to the Trees!

by Jim Steele, August 22, 2019 in WUWT

What’s Natural?

Published in Pacifica. Tribune August 20,2019

This summer I taught a class on the Natural History of the Sierra Nevada for San Francisco State University’s Sierra Nevada Field Campus. The first day we taught students how to identify the trees. Once students know their trees, they can easily see how tree species vary with elevation, temperature, moisture, and snow pack. They can see which species colonize open sunny areas and which trees need shade before they can invade. Old time naturalists used trees to identify “life-zones” where different species of mammals, birds, insects and other plants can be found. Furthermore, when you listen to the trees, you can see change.

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Tree rings indicate the warmest decades of the 20th century were the 1930s and 40s, and temperatures have yet to surpass those decades. This divergence between thermometers and trees is best explained by the fact that instrumental temperatures are biased upwards when taken at hot airports or in areas recently suffering from growing urban heat island effects. In contrast, trees measure temperatures in natural habitat.

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